FsStream

FsStream — A stream in a session in a conference

Functions

Properties

FsCodecGList * current-recv-codecs Read
GstStructure * decryption-parameters Read
FsStreamDirection direction Read / Write / Construct
FsCodecGList * negotiated-codecs Read
FsParticipant * participant Read / Write / Construct Only
FsCodecGList * remote-codecs Read
gboolean require-encryption Read / Write
FsSession * session Read / Write / Construct Only

Signals

Types and Values

Object Hierarchy

    GObject
    ╰── FsStream

Includes

#include <farstream/fs-conference.h>

Description

This object is the base implementation of a Farstream Stream. It needs to be derived and implemented by a Farstream conference GStreamer element. A Farstream Stream is a media stream originating from a FsParticipant inside a FsSession. In fact, a FsStream instance is obtained by adding a participant into a session using fs_session_new_stream().

This will communicate asynchronous events to the user through GstMessage of type GST_MESSAGE_ELEMENT sent over the GstBus.

The "farstream-new-local-candidate" message

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"stream"           #FsStream          The stream that emits the message
"candidate"        #FsCandidate       The new candidate

This message is emitted when a new local candidate is discovered.


The "farstream-local-candidates-prepared" message

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"stream"           #FsStream          The stream that emits the message

This signal is emitted when all local candidates have been prepared, an ICE implementation would send its SDP offer or answer.


The "farstream-new-active-candidate-pair" message

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"stream"           #FsStream          The stream that emits the message
"local-candidate"  #FsCandidate       Local candidate being used
"remote-candidate" #FsCandidate       Remote candidate being used

This message is emitted when there is a new active candidate pair that has been established. This is specially useful for ICE where the active candidate pair can change automatically due to network conditions. The user must not modify the candidates and must copy them if he wants to use them outside the callback scope. This message is emitted once per component.


The "farstream-recv-codecs-changed" message

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"stream"           #FsStream          The stream that emits the message
"codecs"           #FsCodecGList      A #GList of #FsCodec

This message is emitted when the content of the “current-recv-codecs” property changes. It is normally emitted right after the “src-pad-added” signal only if that codec was not previously received in this stream, but it can also be emitted if the pad already exists, but the source material that will come to it is different. The list of new recv-codecs is included in the message


The "farstream-component-state-changed" message

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"stream"           #FsStream          The stream that emits the message
"component"        #guint             The component whose state changed
"state"            #FsStreamState     The new state of the component

This message is emitted the state of a component of a stream changes.

Functions

fs_stream_set_transmitter ()

gboolean
fs_stream_set_transmitter (FsStream *stream,
                           const gchar *transmitter,
                           GParameter *stream_transmitter_parameters,
                           guint stream_transmitter_n_parameters,
                           GError **error);

Set the transmitter to use for this stream. This function will only succeed once.

The parameters correspond to the varios GObject properties of the selected stream transmitter.

Parameters

stream

a FsStream

 

transmitter

Name of the type of transmitter to use for this stream

 

stream_transmitter_n_parameters

Number of parametrs passed to the stream transmitter

 

stream_transmitter_parameters

an array of n_parameters GParameter struct that will be passed to the newly-create FsStreamTransmitter.

[array length=stream_transmitter_n_parameters][allow-none]

error

location of a GError, or NULL if no error occured

 

Returns

TRUE if the transmitter could be set, FALSE otherwise


fs_stream_set_transmitter_ht ()

gboolean
fs_stream_set_transmitter_ht (FsStream *stream,
                              const gchar *transmitter,
                              GHashTable *stream_transmitter_parameters,
                              GError **error);

Set the transmitter to use for this stream. This function will only succeed once.

The parameters correspond to the varios GObject properties of the selected stream transmitter.

This is the same as fs_stream_set_transmitter() except that the parameters are passed in a GHashTable to make it more friendly to GObject introspection

Parameters

stream

a FsStream

 

transmitter

Name of the type of transmitter to use for this stream

 

stream_transmitter_parameters

A GHashTable of string->GValue containing the parameters.

[element-type utf8 GValue][allow-none]

error

location of a GError, or NULL if no error occured

 

Returns

TRUE if the transmitter could be set, FALSE otherwise


fs_stream_add_remote_candidates ()

gboolean
fs_stream_add_remote_candidates (FsStream *stream,
                                 GList *candidates,
                                 GError **error);

This function adds remote candidates. Any new candidates are added to the list. The candidates will be used to establish a connection with the peer. A copy will be made so the user must free the passed candidate using fs_candidate_destroy() when done.

Parameters

stream

an FsStream

 

candidates

an GList of FsCandidate representing the remote candidates.

[element-type FsCandidate]

error

location of a GError, or NULL if no error occured

 

Returns

TRUE if the candidate was valid, FALSE otherwise


fs_stream_set_remote_codecs ()

gboolean
fs_stream_set_remote_codecs (FsStream *stream,
                             GList *remote_codecs,
                             GError **error);

This function will set the list of remote codecs for this stream. If the given remote codecs couldn't be negotiated with the list of local codecs or already negotiated codecs for the corresponding FsSession, error will be set and FALSE will be returned. The remote_codecs list will be copied so it must be free'd using fs_codec_list_destroy() when done.

Parameters

stream

a FsStream

 

remote_codecs

a GList of FsCodec representing the remote codecs.

[element-type FsCodec]

error

location of a GError, or NULL if no error occured

 

Returns

FALSE if the remote codecs couldn't be set.


fs_stream_force_remote_candidates ()

gboolean
fs_stream_force_remote_candidates (FsStream *stream,
                                   GList *remote_candidates,
                                   GError **error);

This function forces data to be sent immediately to the selected remote candidate, by-passing any connectivity checks. There should be at most one candidate per component.

Parameters

stream

a FsStream

 

remote_candidates

a GList of FsCandidate to force.

[element-type FsCandidate]

error

location of a GError, or NULL if no error occured

 

Returns

TRUE if the candidates could be forced, FALSE otherwise


fs_stream_set_decryption_parameters ()

gboolean
fs_stream_set_decryption_parameters (FsStream *stream,
                                     GstStructure *parameters,
                                     GError **error);

Sets decryption parameters. The exact parameters depend on the type of plugin being used.

Parameters

stream

a FsStream

 

parameters

a GstStructure containing the decryption parameters.

[transfer none]

error

the location where to store a GError or NULL

 

Returns

TRUE if the decryption parameters could be set, FALSE otherwise

Since: UNRELEASED


fs_stream_destroy ()

void
fs_stream_destroy (FsStream *stream);

This will cause the stream to remove all links to other objects and to remove itself from the FsSession. Once a FsStream has been destroyed, it can not be used anymore.

It is strongly recommended to call this function from the main thread because releasing the application's reference to a stream.

Parameters

stream

a FsStream

 

fs_stream_iterate_src_pads ()

GstIterator *
fs_stream_iterate_src_pads (FsStream *stream);

Creates a GstIterator that can be used to iterate the src pads of this stream. These are the pads that were announced by “src-pad-added” and are still valid.

Parameters

stream

a FsStream

 

Returns

The GstIterator.

[transfer full]


fs_stream_add_id ()

void
fs_stream_add_id (FsStream *stream,
                  guint id);

This function is used to add data identifiers that allow the plugin to recognize packets that are meant for id. For example, in RTP, one would set the SSRCs that are expected.

Depending on the protocol, one may be able to add more than one ID to a stream (in RTP you can have multiple SSRCs in a stream). If a protocol supports only one id, adding a new one will overwrite it. If an ID was already set on a stream, adding it to another stream will override the previdous decision.

For most protocols, calling this function is optional as the incoming data can be matched with a stream by its source IP address. This is mostly useful if one is using multicast or is behind a muxer server.

Parameters

stream

a FsStream

 

id

The id to add to the stream

 

fs_stream_emit_error ()

void
fs_stream_emit_error (FsStream *stream,
                      gint error_no,
                      const gchar *error_msg);

This function emits the “error”" signal, it should only be called by subclasses.

Parameters

stream

FsStream on which to emit the error signal

 

error_no

The number of the error

 

error_msg

Error message to be displayed to user

 

fs_stream_emit_src_pad_added ()

void
fs_stream_emit_src_pad_added (FsStream *stream,
                              GstPad *pad,
                              FsCodec *codec);

Emits the “src-pad-added”" signal, it should only be called by subclasses.

Parameters

stream

FsStream on which to emit the src-pad-added signal

 

pad

the GstPad that this FsStream has created

 

codec

The FsCodec for this pad

 

Types and Values

struct FsStream

struct FsStream;

All members are private, access them using methods and properties


struct FsStreamClass

struct FsStreamClass {
  GObjectClass parent_class;

  /*virtual functions */
  gboolean (*add_remote_candidates) (FsStream *stream,
                                     GList *candidates,
                                     GError **error);

  gboolean (*force_remote_candidates) (FsStream *stream,
      GList *remote_candidates,
      GError **error);

  gboolean (*set_remote_codecs) (FsStream *stream,
                                 GList *remote_codecs, GError **error);

  void (*add_id) (FsStream *stream,
                  guint id);

  gboolean (*set_transmitter) (FsStream *stream,
      const gchar *transmitter,
      GParameter *stream_transmitter_parameters,
      guint stream_transmitter_n_parameters,
      GError **error);

  gboolean (* set_decryption_parameters) (FsStream *stream,
      GstStructure *parameters, GError **error);
};

You must override add_remote_candidate in a subclass. If you have to negotiate codecs, then you must override set_remote_codecs too

Members

GObjectClass parent_class;

Our parent

 

add_remote_candidates ()

Set sthe remote candidates

 

force_remote_candidates ()

Forces certain remote candidates

 

set_remote_codecs ()

Sets the list of remote codecs

 

add_id ()

Add a known id to be associated with this stream

 

set_transmitter ()

Set the transmitter to use for this stream

 

set_decryption_parameters ()

Set decryption parameters

 

enum FsStreamDirection

An enum for specifying the direction of a stream

Members

FS_DIRECTION_NONE

No direction specified

 

FS_DIRECTION_SEND

Send only

 

FS_DIRECTION_RECV

Receive only

 

FS_DIRECTION_BOTH

Send and receive

 

enum FsStreamState

These are the possible states of a stream, a simple multicast stream could only be in "disconnected" or "ready" state. An stream using an ICE transmitter would use all of these.

Members

FS_STREAM_STATE_FAILED

connectivity checks have been completed, but connectivity was not established

 

FS_STREAM_STATE_DISCONNECTED

no activity scheduled

 

FS_STREAM_STATE_GATHERING

gathering local candidates

 

FS_STREAM_STATE_CONNECTING

establishing connectivity

 

FS_STREAM_STATE_CONNECTED

at least one working candidate pair

 

FS_STREAM_STATE_READY

ICE concluded, candidate pair selection is now final

 

Property Details

The “current-recv-codecs” property

  “current-recv-codecs”      FsCodecGList *

This is the list of codecs that have been received by this stream. The user must free the list if fs_codec_list_destroy(). The "farstream-recv-codecs-changed" message is send on the GstBus when the value of this property changes. It is normally emitted right after “src-pad-added” only if that codec was not previously received in this stream, but it can also be emitted if the pad already exists, but the source material that will come to it is different.

[transfer full]

Flags: Read


The “decryption-parameters” property

  “decryption-parameters”    GstStructure *

Retrieves previously set decryption parameters

Flags: Read


The “direction” property

  “direction”                FsStreamDirection

The direction of the stream. This property is set initially as a parameter to the fs_session_new_stream() function. It can be changed later if required by setting this property.

Flags: Read / Write / Construct


The “negotiated-codecs” property

  “negotiated-codecs”        FsCodecGList *

This is the list of negotiatied codecs, it is the same list as the list of FsCodec from the parent FsSession, except that the codec config data has been replaced with the data from the remote codecs for this stream. This is the list of FsCodec used to receive data from this stream. It is a GList of FsCodec.

[transfer full]

Flags: Read


The “participant” property

  “participant”              FsParticipant *

The FsParticipant for this stream. This property is a construct param and is read-only construction.

Flags: Read / Write / Construct Only


The “remote-codecs” property

  “remote-codecs”            FsCodecGList *

This is the list of remote codecs for this stream. They must be set by the user as soon as they are known using fs_stream_set_remote_codecs() (generally through external signaling). It is a GList of FsCodec.

[transfer full]

Flags: Read


The “require-encryption” property

  “require-encryption”       gboolean

If set to TRUE, only encrypted content will be accepted on this stream.

Flags: Read / Write

Default value: FALSE


The “session” property

  “session”                  FsSession *

The FsSession for this stream. This property is a construct param and is read-only construction.

Flags: Read / Write / Construct Only

Signal Details

The “error” signal

void
user_function (FsStream *self,
               FsError   errorno,
               gchar    *error_msg,
               gpointer  user_data)

This signal is emitted in any error condition

Parameters

self

FsStream that emitted the signal

 

errorno

The number of the error

 

error_msg

Error message to be displayed to user

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last


The “src-pad-added” signal

void
user_function (FsStream *self,
               GstPad   *pad,
               FsCodec  *codec,
               gpointer  user_data)

This signal is emitted when a new gst source pad has been created for a specific codec being received. There will be a different source pad for each codec that is received. The user must ref the GstPad if he wants to keep it. The user should not modify the FsCodec and must copy it if he wants to use it outside the callback scope.

This signal is not emitted on the main thread, but on GStreamer's streaming thread!

Parameters

self

FsStream that emitted the signal

 

pad

GstPad of the new source pad

 

codec

FsCodec of the codec being received on the new source pad

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last